Pumping of helium and hydrogen by sputter-ion pumps. I. Helium pumping

This article is divided into two parts. Part I deals with the pumping of helium by sputter-ion pumps, where Part II, to follow in a subsequent publication in this journal, deals exclusively with the pumping of hydrogen. In Part I, quantitative data are given for the He speeds and capacities of both noble and conventional diode and triode pumps. The effectiveness of various pump regeneration procedures, subsequent to the pumping of He, is reported. These included bakeout and N2 glow discharge cleaning. The comparative desorption of He with the subsequent pumping of N2 is reported on. The N2 speeds of these pumps were used as the benchmarks for defining the size of the pumps versus their respective He speeds